haystack-react/dist/useHaystackRecordTag.d.ts

Project Haystack utilities for building React applications

import { HDict, HGrid, HRef, HVal } from 'haystack-core';
/**
 * A Haystack record.
 */
export interface Record extends HDict {
    /**
     * Id of the record
     */
    id?: HRef;
}
/**
 * A hook to use a record tag from an haystack server as react state.
 *
 * IMPORTANT: writing is currently only supported with a FIN 5/SkySpark server.
 *
 * IMPORTANT: This hooks requires a ClientContext to work. @see https://github.com/j2inn/haystack-nclient
 *
 * @example <caption>Example of usage for a precision tag of type Number.</caption>
 *
 * const record = useReadByFilter('precision and point and temp and zone and sp').grid[0] // One-shot reading the first record that matches the filter
 * const [precision, setPrecision, updatedRecord] = useHaystackRecordTag<HNum>(record, "precision") // Using its tag state
 *
 * @param originalRecord record dict used to retrieve id and initial value.
 * @param tagName name of the tag.
 * @param pollRate poll rate for the value subscription. Expressed in seconds.
 * @returns Returns the point value, a function to update it and the point dict.
 */
export declare function useHaystackRecordTag<Value extends HVal>(originalRecord?: Record, tagName?: string, pollRate?: number): [Optional<Value>, RecordTagWriteFunc<Value> | undefined, Optional<Record>];
type Optional<Value> = Value | undefined | null;
type RecordTagWriteFunc<Value extends HVal> = (val?: Value) => Promise<HGrid<HDict>>;
export {};